The First Battle of Bull Run, also known as the First Battle of Manassas (the name used by Confederate forces), was the first major land battle of the American Civil War, fought on July 21, 1861, near Manassas, Virginia.

1st Battle of Bull Run Union Order of Battle

UNION ARMY
Brig. Gen. IRVIN McDOWELL, COMMANDING

    FIRST DIVISION.
    Brig. Gen. DANIEL TYLER.

    First Brigade
    Col. E. D. KEYES.

    Second Maine.
    First Connecticut.
    Second Connecticut.
    Third Connecticut.

    Second Brigade.
    Brig. Gen. R. C. SCHENCK.

    Second New York (State Militia).
    First Ohio.
    Second Ohio.
    E, Second U.S. Artillery.

    Third Brigade.
    Col. W. T. SHERMAN.

    Thirteenth New York.
    Sixty-ninth New York.
    Seventy-ninth New York.
    Second Wisconsin.
    E, Third U.S. Artillery.

    Fourth Brigade.
    Col. I. B. RICHARDSON,

    First Massachusetts.
    Twelfth New York.
    Second Michigan.
    Third Michigan.
    G, First U.S. Artillery.
    M, Second U.S. Artillery.

    SECOND DIVISION.
    Col. ANDREW PORTER.

    First Brigade.
    Col. Andrew Porter.

    Eighth New York (Militia).
    Fourteenth New York.
    Twenty-seventh Now York.
    Battalion U.S. Infantry.
    Battalion U.S. Marines.
    Battalion U.S. Cavalry.
    D, Fifth U.S. Artillery.

    Second Brigade.
    Col. A. E. Burnside.

    Second New Hampshire.
    First Rhode Island.
    Second Rhode Island.
    Seventy-first New York.

    THIRD DIVISION.
    Col. S. P. HEINTZELMAN, wounded.

    First Brigade.
    Col. W. B. FRANKLIN.

    Fifth Massachusetts.
    Eleventh Massachusetts.
    First Minnesota.
    I, First U.S. Artillery.

    Second Brigade.
    Col. O. B. WILLCOX, wounded and captured.

    Eleventh New York (Fire Zouaves).
    Thirty-eighth New York.
    First Michigan.
    Fourth Michigan.
    D, Second U.S. Artillery.

    Third Brigade.
    Col. O. O. HOWARD.

    Third Maine.
    Fourth Maine.
    Fifth Maine.
    Second Vermont.

    FOURTH (RESERVE) DIVISION.
    Brig. Gen. THEODORE RUNYON.

    First New Jersey.
    Second New Jersey.
    Third New Jersey.
    Third New Jersey.

    First New Jersey.
    Second New Jersey.
    Fourth New Jersey.
    Forty-first New York.

    FIFTH DIVISION.
    Col. DIXON S. MILES.

    First Brigade.
    Col. Louis BLENKER.

    Eighth New York (Volunteers).
    Twenty-ninth New York.
    Thirty-ninth New York.
    Twenty-seventh Pennsylvania.
    A, Second U.S. Artillery.
    Bookwood's New York Battery.

    Second Brigade.
    Col. THOMAS A. DAVIES.

    Sixteenth New York.
    Eighteenth New York.
    Thirty-first New York.
    Thirty-second New York.
    G, Second U.S. Artillery.





1st Battle of Bull Run Confederate Order of Battle

    ARMY OF THE POTOMAC (AFTERWARDS FIRST CORPS), JULY 21, 1861

    Brig. Gen. G. T. BEAUREGARD.

CSA INFANTRY

    First Brigade
    Brig. Gen. M. L. BONHAM

    Eleventh North Carolina.
    Second South Carolina.
    Third South Carolina.
    Seventh South Carolina.
    Eighth South Carolina.

    Brig. Gen. R. S. EWELL.

    Fifth Alabama.
    Sixth Alabama.
    Sixth Louisiana.

    Third Brigade.
    Brig. Gen. D. R. JONES

    Seventeenth Mississippi.
    Eighteenth Mississippi.
    South Carolina.

    Fourth Brigade.
    Brig. Gen. J. LONGSTREET.

    Fifth North Carolina.
    First Virginia.
    Eleventh Virginia.
    Seventeenth Virginia.

    Fifth Brigade.
    Col. P. ST. GEORGE Cocke

    First Louisiana Battalion.
    Eighth Virginia, seven companies.
    Eighteenth Virginia.
    Nineteenth Virginia.
    Twenty-eighth Virginia.
    Forty-ninth Virginia, three companies.

    Sixth Brigade.
    Col. J. A. EARLY.

    Thirteenth Mississippi.
    Fourth South Carolina.
    Seventh Virginia.
    Twenty-fourth Virginia.

    (*) From a field return for that date, but dated September 25, 1861. The reports following show other combinations during the battle. See Nos. 81, 85, and 92 for distribution of artillery and cavalry; No. 110 for organization of a Seventh Brigade; and No. 115 for the composition of Holmes' Brigade.

    Troops not brigaded.

    Seventh Louisiana Infantry.
    Eighth Louisiana Infantry.
    Hampton Legion (South Carolina) Infantry.
    Thirtieth Virginia Cavalry.
    Harrison's Battalion Cavalry.
    Independent Companies (ten)Cavalry.
    Washington (Louisiana) Battalion Artillery.

    ARTILLERY.

    Kemper's Battery.
    Latham's Battery.
    Loudoun Battery.
    Shields' Battery.
    Camp Pickens Companies.




    "ARMY OF THE SHENANDOAH" (JOHNSTON'S DIVISION), JUNE 30, 1861.

    Brig. Gen. JOSEPH E. JOHNSTON.

    First Brigade.
    COL. T. J. JACKSON.

    Second Virginia Infantry.
    Fourth Virginia Infantry.
    Fifth Virginia Infantry.
    Twenty-seventh Virginia Infantry.
    Pendleton's Battery.

    Second Brigade.
    Col. F. S. BARTOW.

    Seventh Georgia Infantry.
    Eighth Georgia Infantry.
    Ninth Georgia Infantry.
    Duncan's Kentucky Battalion.
    Pope's Kentucky Battalion.
    Alburtis' Battery.

    Third Brigade.
    Brig. Gen. B. E. BEE.

    Fourth Alabama Infantry.
    Second Mississippi Infantry.
    Eleventh Mississippi Infantry.
    First Tennessee Infantry.
    Imboden's Battery.

    Fourth Brigade.
    Col. A. ELZEY.

    First Maryland (Battalion) Infantry.
    Third Tennessee Infantry.
    Tenth Virginia Infantry.
    Thirteenth Virginia Infantry.
    Grove's Battery.

    Not brigaded.

    First Virginia Cavalry.     Col. J.E.B. Stuart
    Thirty-third Virginia Infantry.


PRIMARY SOURCES:

The Battle of Bull Run (1st Manassas) (http://www.civilwarhome.com/1manassa.htm)